The present disclosure is directed to cutting tools and more particularly to snips and shears for cutting sheet metal and other stiff or rigid sheet materials.
Conventional sheet metal snips, commonly known as aviation snips, comprise pivotally connected lower and upper blades, and a pair of handles connected to the blades in a manner to maximize mechanical leverage. When cutting sheet material, the blades are orientated to cut perpendicularly to the sheet material. The lower blade is on one side of the sheet, e.g., underneath, while the upper blade is on the other side of the sheet, e.g., on top.
Conventional snips are designed to cut either left or right curves. With left snips, the lower blade is on the left side, in the user""s direction of cutting. In right snips, the lower blade is on the right side. By industry custom left snips have red handles and right snips have green handles. It is difficult, cumbersome and at many times impossible to cut a curve to the left with right snips or to cut right curves with left snips because of interference between the sheet material and the tool. For example, if one attempts to cut a curve to the right with left snips, the left portion of the freshly cut sheet material will move upwardly into interfering contact with the upper blade, the handles and the user""s hand. In addition to left and right snips, there are commercially available straight snips (yellow handles) and various specialty snips.
Sheet metal work necessarily requires use of multiple snips, which adds capital cost to sheet metal work. Sheet metal cutting jobs commonly require workers to frequently switch between left and right snips, which is inefficient. One pair of snips often times becomes misplaced or hidden under scrap metal, resulting in further inefficiency.
The tool of the present invention provides for multi-directional cutting of sheet metal and other stiff or rigid sheet materials. The tool can be used to cut left curves, right curves and straight lines. The tool of the invention may be used to cut continuous serpentine curves and irregular patterns without changing tools.
In a basic embodiment, the multi-directional cutting tool of the invention comprises a first shearing member, a second shearing member pivotally connected at one end to the first shearing member, the second shearing member having an opening adjacent the pivot point, and a mechanism connected to the first and second shearing members for pivotally moving the second shearing member relative to said first shearing member. The opening adjacent the one end where the pivotal connection is made, allows sheet material that has been cut to slide over both shearing members. Thereby, either left or right curves may be made.
In a preferred embodiment of the tool of the invention, a first shearing member comprises a substantially horizontally disposed U-shaped member having a first leg and a substantially parallel second leg, at least one of the legs inclined from the horizontal. The first leg has a first cutting edge. A second shearing member comprises a substantially vertically disposed V-shaped shearing member having two arms. An end of a first one of the arms is pivotally mounted to the U-shaped member at the base of the U, in between the first and second legs. The first arm extends in a forward direction parallel to the first leg of the U-shaped member. The second arm of the V-shaped shearing member extends upwardly and rearward from the opposite end of the first arm. The first arm of the shearing member has a second cutting edge which engages the first cutting edge on the U-shaped member. A substantially vertical plate is connected to the second leg of the U-shaped member parallel to and on the side of the V-shaped member opposite the second cutting edge. The vertical plate has a substantially horizontal slot above the U-shaped member and horizontally disposed between the arms of the V-shaped member. The V-shaped shearing member is slideably mounted to the vertical plate. A pair of handles is provided. One of the handles is connected to an upper portion of the vertical plate, and the other handle is operatively connected to an upper portion of the second arm of the V-shaped shearing member. Thereby the handles are spaced above the U-shaped member. The handles operate to pivotally move the shearing members between a first position in which the second cutting edge is in a closed mating position relative to the first cutting edge, and a second position wherein the second cutting edge is in an open position.
The preferred embodiment of the invention may be operated to cut both left and right curves. A preferred method for cutting a curved pattern in a horizontally disposed piece of sheet material is as follows. The tool is positioned with open jaws so that an edge of the sheet material is in between the first and second cutting edges. The handles are operated to pivotally move the shearing members while advancing the tool to cut the sheet material into left and right portions. While cutting, one freshly cut portion (i.e., the portion adjacent the second leg of the U-shaped member) is slid under the U-shaped member, while the other portion (i.e., the portion adjacent the first leg) is slid over the U-shaped member. A curve in the direction of the first leg will result in the U-shaped member sliding over the larger, acutely hooked portion of the freshly cut material. This portion will not interfere with further cutting. A curve in the other direction will cause the sheet material on the side adjacent the first leg to slide over the first arm of the V-shaped member, in between the two arms and through the opening in the vertical plate. As a result, this portion of freshly cut material slides freely over the U-shaped plate and does not interfere with further cutting. Accordingly, the tool may be advanced as desired to cut either left or right curves.
Reference herein to the horizontal and vertical, left and right, up and down, directions is intended to provide a frame of reference and the convey the relative orientation of parts, and should not be construed as limitations on the scope of the invention. The cutting tool of the invention will operate at any angle and even inverted.
Other attributes and benefits of the present invention will become apparent from the following detailed specification when read in conjunction with the accompanying drawings.